Base timing check

[jcoll]

Okay, I've done a search on several of these forums and tried the internet for this information. I'm a bit confused still. I don't have a mercruiser service manual and I'm using a SELOC manual. I'm trying to determine how to check base timing on my engines. I have a 1998 290 Sundancer with 5.0L engines equipped with TBI fuel system and Alpha 1 Gen II outdrives. I see listing calling this system a MEFI 1 or a Delco EST system. I'm familiar with GM's systems on cars and this system looks like an EST system used on many V6 and V8 TBI applications. The confusion comes from if I need a Special Timing Tool or if I only need a jumper wire to put the ignition system into base timing mode and if it's just a jumper wire which terminals on the DLC are jumpered. Can anyone shed some light on this? Thanks for your help.

 

[jcoll]

I'm not seeing any light here. Anybody out there have any help?

 

[Fun Times]

The engine must be at NORMAL OPERATING TEMPERATURE for this adjustment. Two
items of test equipment are required: A inductive pickup timing light and either a Scan Tool, or a Diagnostic Code Tool, or MerCruiser Special Timing Tool (91-805747A1).
http://www.rinda.com/marine/marine.htm

1. Connect timing light to number 1 ignition wire.

2. Connect the appropriate tool to the DLC connector of the wiring harness.

NOTE: The mefi's 2 & 3 will automatically adjust engine to approximately 1200 - 1600 rpm when put in the service or timing mode.

3. On MEFI 1, you will need to Manually adjust the engine throttle to 1800 rpm + or - 200 rpm's.

4. If Not Using MerCruiser Timing Tool: With engine running, set the scan tool or Diagnostic Code Tool to service mode.

5. Shine the timing light at the timing mark indicator located on the timing chain cover.

NOTE: If adjustment is needed, loosen the distributor hold-down bolt and rotate the distributor clockwise or counterclockwise to adjust the timing. Then repeat the timing light check until the specification ( ? degrees BTDC) is met.

6. Torque distributor hold-down bolt to 30 lb-ft (40 Nm).

7. Set Scan Tool or Diagnostic Code Tool to normal mode. If using the MerCruiser Special Timing Tool, disconnect it from DLC connector.

8. Manually close throttle to bring engine down to idle state.


[Note, If you do not have the correct tools to time the engine, then you could do this with a paper clip as well, you just short A and B together at the data link connector.:wink:
​

 

[jcoll]

Thanks Boat Tech. I thought a paper clip would do the trick. :smt001 It was the most valuable tool in the shop when OBD I GM's came in for Ck. engine lights. We had plenty of scanners but it was usually quicker to get to a paper clip. Do you know the wire colors for terminals A and B assuming they're the same from year to year? Or a postive way to tell which are A and B - which end do I start from?

 

[Fun Times]

No problem.:smt001

Thanks Boat Tech. I thought a paper clip would do the trick. :smt001 It was the most valuable tool in the shop when OBD I GM's came in for Ck. engine lights. We had plenty of scanners but it was usually quicker to get to a paper clip. Do you know the wire colors for terminals A and B assuming they're the same from year to year? Or a postive way to tell which are A and B - which end do I start from?

On your DLC connector to your engine model,

Terminal (A) will be a black wire with a white stripe on it. Terminal (A) is going to ground.

Terminal (B) will be a white wire with a black stripe on it. Terminal (B) is going to ECM.

Have fun.:thumbsup:

 

[jcoll]

Thanks, that's a big help.